SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad7d6102ae4087a697c2f476d576e3209707cbaf816db768ee720beff86842a2' 
  AND token = 'WDSd28ZiUhbiHEYh8q8Pi3h3y2nT9aTRsy9WBmyCT9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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