SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '60d4b543145e38dfacadffdee74470c0bee91cf0489c3cdffa08be2ad030a983' 
  AND token = 'Z99LHqR5j6ycn65uyjwyX9fDBEgrnDCoarJ99nTN0ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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