SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4e6856fa5957f4828d2c5b52b9ae85111019936c2af7cfc6077a32f085315684' 
  AND token = '0urAESLSy6gVkeseJEIGI3mINAUlrqAy+VKw81IYjIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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