SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad151d3a38db868f814b366236f81ba53447cb74f5fff004aae681923f3ae93' 
  AND token = 'yj+PjeBY0nxcwT6zmOd0CByCqscKrot3UQF6Mr9RlTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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