SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e15eb10372efdd6c0935968970794dd512e67e54588ce470ca6caa47aae227f1' 
  AND token = 'JPCSe0TztWmy/QTxsHlBMB51um0Y5690I6WDOV2p9Cw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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