SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb7c1c9a9ea37330615b3df8d88c64094f8d58dbd9b7f37224edcac2604c04b1' 
  AND token = '+WLhQt5kMPy9U+DYpAjJw7KfBSzDQ/eROxnj8OwpzsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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