SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a8ebbcc9eaeebf7a088b7c2418dc2cbe3efb81b7897570cd1d747d71befde2e' 
  AND token = 'oaFXScCMR+06kAvLjxM3CKmYir3fcwpZ7XZQzlsAMXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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