SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51307105f5e1ff0f8990cb6efff0d8ecdbaa90661ecc968ed823742e5b3197e9' 
  AND token = 'TYnDjVxa58LAFiiuGke4ZPxisj76oidsyJXT6pA4sH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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