SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cdec45878874c0f1e3508880b30587511bb3f99655183c6697d118acccea15f' 
  AND token = 'nRNmyrAlQljM9yGcoIeTHF/1wKKN81DHiPRSDmohxKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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