SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '66908a082df88423e3970eead9526374291d1608d645cec881c8535b109ebcdb' 
  AND token = 'x91VrxDD9aYukLKZoptyUbyPk66DH/f/J7/k3VWP3WQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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