SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1ef8f0fd87c9c7467ddabdeb2b472218e931255994dec4b224031ee99ae5263' 
  AND token = 'QFnMiiscMvvWhl/ImV3PuywdSGf/TVCq+1hkJ0NCidA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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