SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b94a105dd9a03cc2bd8d4d08486728ea8260b988d399ef444d54ad53787e51dd' 
  AND token = 'qh23vI3prtRcXMCqMX41uoGWeoKV84yiGQRf7yRBkkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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