SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '848cdfb26061f3e5e27f245a6f9285a17516b23ccba951306a2465f08ce98ecf' 
  AND token = '1dzBpTVIsxqb35+49yUQPlzlerWufXasmCyePhrK2OU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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