SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a08b8328bd5afd66693ea111da420c7379b7bf3d500732c495c1012f046cc88f' 
  AND token = '0ejqp1XTuqUuf4J7Cu9jbX6D9AMe1BKu5Hp9S/dMxLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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