SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e369f8fce0943921dc482b684e74b38afe3fcb9f26e4c601b093fa5777a7f9e' 
  AND token = 'YJt+EH8Ub1ijXYQCUFJLkWYjQQmDoci+vUn0M9Wqb9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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