SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f515e04d538a713c0ffdc71674b88e34ddf228ef6d221bd13f6eca58cddb40f' 
  AND token = 'y+lP+QWfFTIacaIkmfgYbH1KThdM7FGGtgK+eicNxjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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