SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b4ea79a59b8d5befa0bc18f17360466972cf9292c6e50e8856caa1e9214303f' 
  AND token = 'opfLVGqVZbF2om657ApZHMUujU2ZQHY4EQnpmzsvw8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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