SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b8e84689f5b75a842f88b862896788c6d6af0860cf551685ecfa00f27e910d6b' 
  AND token = 'O/KvinLfdRal5twV0lNh65DgUpUsNv7h4V+O30C41NI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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