SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e3d4bbc7b7465baec63f9894b216a76be8310b6d7edfa5409eabd0a120ee3f6' 
  AND token = 'Rq8yqvHkmJ8MqEfJTq1vwvZrtsubHelOAQF6CBg7g+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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