SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b7b899034c3ce8454414d7ae5fd8c972aa6af06b18296eb8ef5dd325846d4774' 
  AND token = 'sz5y0oU17EiQdyOGsa6hZjDdLPW4vNRpKGjCU8qtgXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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