SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'af565f172737fd3e7f9a691f0dfc80c197c5238ee18a1ab33d372efd07b62621' 
  AND token = 'nJxs9ckWz4YF8n/7NQKau9CyT+FgLyBM3TgCgVeawD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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