SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b7efd77e7f83624f9af48101b7e2fa516ed42f9db792fd0ea4008a0850e5daa' 
  AND token = 'cyRYugHfN9M6Wot1uewSw8lhfXgBhTzf7cjdApoXnNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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