SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ef911df94ba835c92bf9776654d4945a1fecea0444604fdc71f3b7618fed45b' 
  AND token = 'MLBCJmznjUvIrN/aQTxOJBuu8zBcWvYUX2YViB3MPqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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