SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb3de3d06360e3cb816f306f5bd20a5aef449910e3661bab82ad158da74984f9' 
  AND token = '9V/peEIQeikgf1jfMcw4ztOmToJC/yhtoWr6IaXqhnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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