SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b2f0ad1a4f31d0bb442888d7c9ce3953a53e1d9e21c32a589cb46d2bd58ac7a' 
  AND token = 'rnnsmVmlzGYMxCSVFYB/fuCCRqaDZPa+PNoTGKX+Wkk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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