SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5ef784dae5284832154f56b9508c4be1d693f38f1a1052ddd3e7ac573443bce' 
  AND token = 'j0jUC31eEmtufmeseRURD4zli5vq6pX+tFeNOfIBAhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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