SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8542a4f1f02bb3d6118afde18547292f269bf81c59b05b973faa25d9065e26c1' 
  AND token = 'LwM5g8DNk10A77OT990Y17omBxJgTKt+YLmDx33Tnd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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