SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2918e80cae9151f0869c66d759968e9d26c45aff5dff3821373ca5e55b230d33' 
  AND token = '0j5na3914w6sKSPc1hiznvR56xTYCejYhaIccJvNn0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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