SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a213635cf0c668a6e34630569f4191947f276eff81c1152dafadaf75ca4a302' 
  AND token = 'kZghKk5CMWKNLdvfdNcVLIV5vOE/xIdviEtXfE233p0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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