SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b42bf836d49ea19fcc5f2358eadd2815438a9908a10489fc1a502dce773385a' 
  AND token = '2nteGJNrSphvgV8hGCI6e4YQjnQhR2WXmr5zUWqa7Po=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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