SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6921d6d9c02c860de82c6e5fc1c5b17dff49f3302820f524ff30ecf0001f3dac' 
  AND token = 'ZT47Yw/COB1iVuOkNADhgvbCrsUQHzp1dLUZTkAQGwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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