SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e620fee014c1da4cb45f5ad8b9a91cf5bcd819675de5442cb71da0852b1c0e8a' 
  AND token = 'qWjfWxelzbWFtbAOK79+gPhXadWx0xXyDzL0ZTem2Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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