SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37e977c1c52c2cbf23ade5d16c018feef15c148aec0f1523ddbd1b99d6bbb5e2' 
  AND token = 'QlXYtNt5Wn7226BbWYYPava1msM5718LpaIggSrdS0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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