SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bb85739949f4b9baf7a80b75f3b02f42acd6aae7a57ed731c593266fb9d351a' 
  AND token = 'VBHRcVmiCZZIA82YkR3hjlLQFtVOyCjKWvI0uTetD4A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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