SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8204712b9e537668395c14e1f56383976a1b945d263cac9324cacb7e6db55df' 
  AND token = 'xWVhqCKvJGnrbWSjyw/cY8veQFBlcMNF2mhmBreZfx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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