SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa330ce507f7b47cdd7be2f9db085f6bcb6e08f125429fcde5970ad7fa1c7d8d' 
  AND token = '1GtMMPqXUVEgRRCJXYMp/YfRVPSPtWx1z+msBLRj87Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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