SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca31166480bf73d96dd149961af4a872be0ece30bf5adbc946c1c0c9b2a0ca59' 
  AND token = 'YnLZSjcc4iPKdgpuhQiuWSbQxtBzs5DkYhrn4tBP7Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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