SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c975b570e5762afec5415805cea02e33ee8244f68d8dd9b4dde9176ba6d44eb' 
  AND token = 'A1uklhDVj7qNIU9BvDhnYwa/bOYXEY4GVgmMUz0xlaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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