SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4269cbae436112778b99f7c386a17dbc21e881501373ca858ab0640ddb3bf6a' 
  AND token = 'q4GDCPvc0Ue49sVSAvIDhE2K8g2RwLuMPhbbwPhjg14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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