SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '16a1213d0e8f8c3752c73f97a44b26dd5c12e2d872e6be0b05473208ea8d7524' 
  AND token = 'VFQqfiXK9NVXcKZJNyfFFKrpwouHAG2FXIjQGqcoP/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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