SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd196e058b51e0af4208d0712985ad0d912c744bfdae3879a218800fca626ce48' 
  AND token = 'Y9b7ZcmbPLrRbFocz8w2qY7oMEzvCU7t1v39uSyTL/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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