SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0c7dd4672febc28400e7cb8caa3eabedff8524f70764191f3eee032a249859c' 
  AND token = 's1EAgSSH0DJ4O08Ygi+4EfFW1NXaw27WH9nA7v7ZIlA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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