SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd1d7758cda744db07f6486b76e0f804c986f9f669482c4a4daff367f42ff830' 
  AND token = 'Z46EJlDexl81HRY4tCr+m4UldKDf2LlDMwceiYyKoKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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