SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e778a7ca6e21d9699d82c6ac30802f30b2ad43d0af4b85da0801dcaf84cd528' 
  AND token = 'LXQ6CmmbsYFEZ/754ACATNtB7tu3UEvHWJDM8QyBSps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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