SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a0c9aa71a3812d16df755fdbf3c9ab7377f56636853188f7715eea6afe228d5' 
  AND token = 'C/4uCFKxQ4K3ICyjrpewMZRBQpQOAr7xG5GVsav2Jyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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