SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c97ba15d6877cb49f7df0608b6b659f25bfa525db0d031f19465ce5da65fb03' 
  AND token = 'RjefP5naX2ArUH9RjJeoeWTPM8RDeGKH/26m0xOowp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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