SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b2f0eca1fdda22aeba9fc4673f749d895179d22a530a6f3ef7b5490b0b9e761a' 
  AND token = 'Q/F7DZURhN65RJ4CUJuO9aLTYhcB+wph0t2AJVYXLO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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