SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4666c5888916e7b56552b696371d7e83a54d630c95edffaaf9bf7a8ab7ddd494' 
  AND token = 'zuhOzKsy+OESXeQfkgooMmVCfgsvEl2u0JmojBJ1mmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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