SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32eec31a99cbac06029fd551aaa48f963d270d2a9053bac27242a4c50952df2c' 
  AND token = 'NDnGJonaa6HRBgaMgxKNmbeQhahHlrpjTzRAa+IaEVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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