SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3129bf1a5152db43a6eb98c66c8d9c066aab2d31e2eb55a025348443a429f475' 
  AND token = 'HVZNJ2BjQIuUTNJoUaFThlc08FebIlhQWBOXYAcZwy0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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