SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3fdf1c55ba082214ff2a2929fe9842d2e184a17f28f8b740076c198930d3e9c' 
  AND token = 'Lv/LOoA8jGH54uYXLimQflWBxy/sP7zU+n0ozMyw0tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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