SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e50ad188e219c27a91d2a33aea41dc21111ce65b1e4997a7d5d65160a076a94' 
  AND token = '+fAdSHfeFXjlQhdf5/ebET0iskhbshKwj8ZbN/FRqwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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