Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b56484fa25cd7f4bc409f4956ca34349212e6d8118d78bc1657c0982d5105a20' 
  AND token = 'DoudOuSBbLpo5omAM+Qm+Ji0ERTJUyqFcM874TqlEnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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