SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '594d06218ceb7794233c3a06f5bb907d0bd88f6914fa1300d4254fd101f4f6c1' 
  AND token = 'hSF4TYDuQxzU0pejflWm3j0VVxcF+wzWxtG3nUgkjxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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