SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '85ad0db3a7e1ce58910e258f48e97253748a21635e548cf4afa6fb9d1bbbe3d5' 
  AND token = 'PKDzAzjzIlTHa4eOmEzyFqBwThBeiCnJJ5vZnnoZ3ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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