SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9243919427e74a3dec8676571bd2c83a10ce6ef41394a88f640f2f6f2402dc7b' 
  AND token = '1fHFlJq/PSZ9RRZGQ3Uc+3arPrAgmO7z+8vdd5s/030=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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