SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ff1ddc78ee7cf2658a05e5dddd8b84c84da241fd2d28685af45adf6eea58470f' 
  AND token = '5D+Omu91GfMs5dgo7W00VMwBBmXyPxLZcdGypnGeMI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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