SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be3ea3bb5099b3f2207888ae7bc9bdc027cb2618d7a4889a7b9a7b37d2a36be6' 
  AND token = 'TkTVve+5UZO0apeZ2spTMRQd6rSl7GQ9ST/FrvBjqJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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