SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'db847d505ef69f1eab1d5430f092dfc765e5e8c729353c2c3194425bd19be6bd' 
  AND token = 'X88vRsdbtGjXiE8LuTZhrd+CrUTX7oyzk1ldC/JtsPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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