SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e349c1427a9287f515607d5db5bcca3a730c37869afacfee3ff98e5c72cc46fe' 
  AND token = 'oew0LksWzGYcejS+AitKuJD1YyNQULalRu8lxWdTN6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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