SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab6ef91292cf3efba8ceb9baf77a7da6331a772556800b0da11b595cf3a5029e' 
  AND token = 'UEv9d8h/AlZ3xYwdKaJj09QJK4iPWT0rcppq6dqxfdY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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