SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24f7b617be66c503236d79f693ded757803acf249b42254e5c3f5ce6f5ee2ac4' 
  AND token = 'B/Z8oY1jUYUuYvGsMLNT5UJ8hwNp7vhMrQTKC6YFR88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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