SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3cb2638a9d180368b12419ca8cce6d9548f0c027288c9d14a671a4b8946deb83' 
  AND token = 'MEy4kghO/Nlj9hAMMQzDEdY1NYw4POV45yrkUGIARXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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