SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ef6f2956543c9bc31b1070651a62dcda97f8874a2f396409d77a18a601b93a4' 
  AND token = 'k6G0pxuahibftYBZwgzLNZzAwe9LxSRP8E9GE8RAs4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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