SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47ead50f324716cd93c7b2423792dfb0961d89c5addba86da206bd44258cecd4' 
  AND token = 'WWQ7EJzCuq4TkpwYDdfcA5ZPSP5xAmY7EbB6h67jBvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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