SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0412517818748b1d8a3e9f1ae70550444959a39f7243d64d2219248f789afc7' 
  AND token = 'xwqH/FBgjIanZkUkrv6NUW/EeXXf+RHcA0SrzcuLMgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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