SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09019a226ea62f533576d44b859b45683a98b1dd1444aae40b72d295bf8b509c' 
  AND token = 'P4/AdvjuByZMdIZzcmaGc9mygg8Q/mrRmGXQhwgI+Ss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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