SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16cb266bf71aaceb76058f3c24cd9b377770c1acbc34679c263d9d754d498d6a' 
  AND token = 'iWGSHayn5PPw+oXQBLMKW4PBvb1aBiAMybsHWpoxs2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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