SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f8bab291be6bbccd62258a65ff2531a02a738d93d26a1d5243f34f6a2d6fa4ad' 
  AND token = 't/vzvWb0qWOgPE5gWTjtfRYWd9sGKduGoD5ahwWLm84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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