SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab7a8e47b21fda87f25bad869d7e21171dfd11e78bb39ac3f1abbecd6061a85f' 
  AND token = 'Tj3FOyxAOEszlb4eJ6ySeyOSY1ItUgrDwyGPeVRjJcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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