SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f97ca9d0c78c030db1fc008c5be4988602d5b9da5806dbeaa4516689e960375' 
  AND token = 'kTa7NmD4/Ydj18K+3oXNydTKhVzChdwZ7HKl8Hl8MII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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