SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f199cc811ea9042acd09da5f8427895635b58400f030c2b961e223e8f6f4f64e' 
  AND token = 'ZEnllCPos5ugudqh1mC9PKQUQFS3vb+7WdphikiBBnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}