SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b858edf1db6855eef98b3215c44a56a922bd863e7dfa61087eb71c82d438a541' 
  AND token = 'lWrfgZIqxpAHvvgB1bOdWwHnMsVaq3D6a0hf5QrFB9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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