SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2800a7ea40bcaf1c664ae001ca7aee60a2091a6ea9ff91ccee15c215b313ea49' 
  AND token = 'p8cU1DIBmOa9d6jg2jlmYeIOx9ESi/x1meCzkFOXPMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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