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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd21ad263ea21c8ff841c1f749a3cdde5307efda9ca7ed57895153a3526dd5466' 
  AND token = 'NZ7pGuO6xkJQy+ptw+lSXj3xs5+gfSmQW3QwsD/88V0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}