SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a29cdbbab3de17e7515e06332b4cef429985ad0c1c4e396d619f95ea4014e144' 
  AND token = 'DpKUvg/a/tuB+46sS4wIgvW+0xe8umN/TGYUDQQlpXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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