SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f6c90f2bf6f7caaf1234e7ae7e75c916dd6eb4a996e340309928cbf4ffcbc90' 
  AND token = 'ymAet7xSqqhPf+Jkh8XC1JVUaKFqaFgDi121/SKRwbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}