SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aff555f3e083e9cb4e5d74f559777e2643b2d0f6a8553cba9b7874c38c9c1962' 
  AND token = 'KxIuiNy99be9idTk8Td4+gGKenjg8Ls1zeia1I9NpQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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