SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b8ec2653106bc6101ff5b1af7b159fd18a1ffb149dc0418af484f80255cc35a' 
  AND token = 'e+XftqDN6oOWg6ViYoEjkpWaJM2B3+aX5WVDMBw1h7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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