SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2ac4ff61eb88df1c91962e55367082627c1eb439c8b9c70c4c88e7afe8d611af' 
  AND token = 'hLx81fUunLdQUIqx9XdCH4UCHGLjtaqMkYSThLsNWmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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