SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cc9a76b2f8aa403bac1f79b39a6c231a3783271901ceb27d4f28915bf49808c' 
  AND token = 'X32jZvdL/Rdts+UvC00wWpJKgYeCzTzoYPKjQGBaUU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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