SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71b0809b94a16b4fb61bc73bba5805085daa14f59de7c59c70d53a45c58bd8e3' 
  AND token = 'qt9mhuklSsW8BSY2l38UaG+ZKXTL78F/l1RnXQzEyyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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