SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76dcd8e75907a64b55bac79f8a381a7dbb250d21ffc4917057973fc7ba4cd063' 
  AND token = 'LbTx6Wrynujhe3vOleZ+LitThSvuJ84eqyvdFNsy5+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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