SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2b6b8cb56f9e6685beea6afdb51fb9ed42a0fb75bcd2d3d9cddc2d065627356' 
  AND token = 'oe29auYaZMyww2p23efSF/mnXSUooQSp4JHgZMNyrXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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