SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4907e25896fd1df56ad336bad0dda1f81004d15f1c0cba179646b7515deb55c' 
  AND token = 'hZbXIks/ynD75mfPfB52ZlfmzbMs6+AKAnBCanXqwtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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