SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eec6fc29e196b8ea9ce972539569b6c7a8726a97f98989c050a38ec561713a51' 
  AND token = 'jcaZjqDPQEZpuxkrM1qjpc+sBTjAK6+2IwZzxK5qtxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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