SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e994683bce72d0afdf039d237dd27e57a020b5739b35abe2da7684f90533c646' 
  AND token = 'kRwArYKch+MK+tTnwc2dMScFknunSJzJ6csKWNM7Nl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}