SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a3e45ecd61ba9f94beb2d282ef6201fcb4615dfae6992b056670c66aaef9ea' 
  AND token = 'h/tSZfYTcq+SyFpmSRg/NWEPcU6GWLumOqPL9VHfWmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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