SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c8ead9b96e76a95a16bf3b5a7e48bf96cd212255f78d717733f700a8f4d7957' 
  AND token = 'K4fIsG9ouQFp0svYq+hJkRAbaZ1w1HmC8pdxM0h0zOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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