SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7079a467327b85465fdf96727adc566dec6fee1da3325522e0a7c3af8a99f282' 
  AND token = 'ruNuFYOieDbIrTpRXpSFq7ViREMjBi9vbUd5mDwcs6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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