SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1c6f913ce7c87dd6ddf47b39f768fb4d3cf1e73bf823577a6c517a704ea4e7f' 
  AND token = 'VDNhliG9MGQeBSzmq+O2Ygsnr5Cj906+tkepsXS/L/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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