SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c2c639489eccdabc3b1bbaea3f09b4f50f32d4c2f58355d6dfb16bc020e66ad' 
  AND token = 'W8lOwUFZx6KwqT/WcIsJhIH67C6PE1TZGr6G137va2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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