SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db7da830b36f4517095f9ee12f3ea20167500112a7c1e2a9f822f9f820231456' 
  AND token = 'jodnNNLehUqIKhprJnmRsoFS4mECJcFJ9jnz3ybuq/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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