SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a42b3cf093859d033eae1aac506183260d92c3f45efe33167c1595ac1b98f23' 
  AND token = 'trmyV26cAqjOD6FGTHpW2lG/vghTDzdLfmXNvtHl9tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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