SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8773cb0b5dec213575b853856f0ffbe2d8f5ef77bbbad5026aa5568ace6dc2a3' 
  AND token = 'KzbX65zWj+ipVDrDPdLwMK3zbmYRf/SOsm2m4izKyCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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