SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26f920cd707346fd3655ec037e137d94f35d68b555bd10420a2313f3ae5b6007' 
  AND token = 't3F6voW//FjFSehGQ1AJS0QhAdPTK4GQWP5TqTtPsgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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