SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '57a242dcbe37b2edae83d4f6d16c6e81687c066c4779ce706540cd1e37c0bc4c' 
  AND token = '/tsPsUywzM0sbJfIOB6IrCwRYoYaPd1dHQdQpyBM2Fc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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