SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15559bed5cac828af6303e5afe82c2b0d6ce166a990d02d064d1ec75e9fe0ff1' 
  AND token = 'n+HrSPPcC2/AXtUVVCDumBEaIxphxj63QgX6RdpzNJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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