SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5b7e66ed6632549c8d2624a60ad1f255cc5c476e914da8a0bbeed60c4b7cdbd' 
  AND token = 'tgCWHTAvUPL9RIaXuKTHVIsDc06J8uAQjS0Qs9CgUH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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