SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'db5850c6afb506eab25334eb8f17bc2b6e8ba63144df332f3c6b5eaa1c8d1675' 
  AND token = '4NHGdcyD9lgS0COjsYe7/av8qomIVLJwBvminKJl6iI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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