SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfd626dbb6e997e2b92b2680d14863e6a02b7fb8734b18202e92506f661a12aa' 
  AND token = '3j3PkDL/gNJtAUDXYzz6MVZcenzLpxalmtnotHnzdII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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