SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc0b21b91613c910347a325bd32ebdadbd80371add4b4f27df1988c8bbf99cac' 
  AND token = 'uREareLKP43HhOGiQLEYCeFyaVjTF5gHWel3CZ85KcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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