SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d304209e523af361d26a73724f5caf5246d0ae85610618716f62b48cd25b3ae' 
  AND token = 'a0mIFlJUHDLl0MhhFVC3Gd5+54lRFK0YRyweIa7EV0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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