SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '210ba8bfb11b9fcd66c8a63d7ba8037bb3bfd78cf3f23a966d38f5be87a028a9' 
  AND token = 'W7W3py3YKKWXZtyJHDpbTZkAkQ47PkzWRgShTt5u7bM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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