SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5a4b23a4bffa9e9783fe2682e2d38072b42390f995ffe7452755778083d4862' 
  AND token = '6AoqOcT7JQamotoVOSNfALDHEldtIu3btbX60MRraWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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