SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef773e61d0a659b30b9f55ca1a4a2bec96742b43684af0a440c6ff81cf67739b' 
  AND token = 'Lj0qThZGNdG0Z2HIfP2x8spT6gh1+wK3/Ushum9IoBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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