SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5246d0ebff87ace1295998509b9c47b06b635bb4f8d64a64968735181264223c' 
  AND token = '4O+X0xwJs6JtHcOoE6mGpI20PrUiZMJBitjf4fZRDu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}