SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f18133ddb310e7c2739660c1c4295950a3ac6883ced07f2040a9f13f5628f9b' 
  AND token = 'yPEwd62PhoCcxKDW89VCpBhmxFqwvL88PGGzzeMvV6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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