SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0f17e6643728886d9a5429721215e88c12f4729fd3a292967fe716d93f85b97' 
  AND token = 'V0bXHB4Q9+IDZgvPPITtUMAKR3GbUdZ9+2WHLdUDpPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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