SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5c961841452fed15d2afedf50722ff00da395fa6f8587f0225c0c7cc74896069' 
  AND token = '3ymAz2UNBbCY1DMtOGD2Xsgd/vqbMbLjEQmOYOOSzzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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