SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39012efe3fa26073767dd94b0c290fcfab742906293bfaa7f3542ab6705729a6' 
  AND token = 'zn9eMKGIqh8b8ddwkI6oGfLRd0JKSXmQF3cfFoNF6X0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}