SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f3f8951b5adecbd2810bd9878c76a1da1aafd3617a4a7334ea6ce91a3260faf' 
  AND token = '+mMi6HMBdCwyJxpQaTQnJc5YDXgPqOWcUxzt9jBCVOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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