SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9deb57b4ce56d61085483a6f9a0f018d75614ac3cea8bbad8d15b43841900716' 
  AND token = 'QajBlhifAOj9YqGAKMJYhfCvbPSSV+XPCvo1IQ11dVg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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