SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd621a1c71208ee5a650e092762dc2d3b4f68027b2bb32b2b438e3ab4b3a4d99' 
  AND token = '/jzLJbgt/5LB5zFmhf69QpsKItOXn6NX8RFTxjUvsZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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